Alzheimer's disease is the most prevalent form of senile dementia. Epidemological studies suggest that 25-50% of all people in their 80's have Alzheimer's disease. There are about 4 million cases in the United States alone. Generally, the first symptom of Alzheimer's disease is memory loss, followed by a decline in reasoning ability and reduced use of speech. Behavioral disorders are also often present. The deterioration appears to be irreversible, and eventually leads to death. There is no effective treatment currently available.
A common feature of Alzheimer's disease and other neurodegenerative diseases is the accumulation of fibrous proteinaceous structures known as neurofibrillary tangles and senile plaques. Neurofilament (NF) protein is the main constituent of neurofibrillary tangles. NF proteins consist of three subunits based on molecular weight: high (NF-H), medium (NF-M) and low (NF-L). NF proteins form filaments via coiled-coil interactions between the structurally conservative rod sequences of NF-H, NF-M and NF-L. These filaments can give rise to neurofibrillary tangles when the NF protein is hyper-phosphorylated. .beta.-amyloid, a protein containing about 42 amino acids, is the major component of senile plaque. .beta.-amyloid can aggregate, giving rise to the plaques.
Many studies have shown that aluminum is found in neurofibrillary tangles and senile plaques. Aluminum can complex with .beta.-amyloid or neurofilament protein. In addition, certain epidemiological studies indicate a link between aluminum in water supplies and the incidence of Alzheimer's disease.